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--- haas:spring2014:data:projects:nodes [2014/01/27 10:07] – [Pointers] wedge
+++ haas:spring2014:data:projects:nodes [2014/01/27 10:58] (current) – [Submission] wedge
@@ Line 11: / Line 11: @@
 To review structs and pointers, and see how these two concepts, when combined, produces the core element of our class explorations.
+=====Reference=====
+You absolutely, positively, MUST watch this video: http://www.youtube.com/watch?v=5VnDaHBi8dM
 =====Structures=====
 As we learned in C, there are two main composite data types available to us:
@@ Line 195: / Line 197: @@
 At present, we have a node called first that we've allocated memory to and altered its contents, that diagram would look as follows:
+{{ :haas:spring2014:data:projects:initalnode.jpg |initial node diagram}}
+Notice how all the elements of the node are dealt with (both value and the next pointer). And first, being a mere pointer to a struct, is a name that points to (because it merely contains the address of) the memory region we **malloc()**'ed and are storing our struct in.
+Now,to link to another node (and put in, say, a 37 for its value) we'd do something along these lines:
+<code c>
+first -> next = (Node *) malloc (sizeof(Node));
+first -> next -> value = 37;
+first -> next -> next = NULL;
+</code>
+And don't forget to update your diagram:
+{{ :haas:spring2014:data:projects:nextnode.jpg |}}
+====Use variables to make it easier to traverse the list====
+Since we need to keep a placeholder on our allocated memory, **first** is more or less immovable in the current context (it is our link to everything).
+You may be noticing the potential for some very long code about to happen (what if we wanted to add a third nod... those next's would become next -> next, and so on). But there's a way to keep it simple (but ambiguous, at least without an updated diagram)... and that is to just use another variable, whose job is to be more of a temporary placeholder. We shall call it **tmp**.
+Here is that same node construction logic, redone using an additional **tmp** node pointer, and also adding in a third node (containing the value 8):
+<code>
+Node *first, *tmp = NULL;
+first = (Node *) malloc (sizeof(Node));
+tmp = first;
+tmp -> value = 12;
+tmp -> next = NULL;
+tmp -> next = (Node *) malloc (sizeof(Node));
+tmp = tmp -> next;
+tmp -> value = 37;
+tmp -> next = NULL;
+tmp -> next = (Node *) malloc (sizeof(Node));
+tmp = tmp -> next;
+tmp -> value = 8;
+tmp -> next = NULL;
+</code>
+Our node diagram now looks as follows (but ideally, you'd have been updating it line by line as this program went along-- do not wait "until the end".... build and update your diagram as changes are happening):
+{{ :haas:spring2014:data:projects:thirdnodeandtmp.jpg |}}
+=====Procedure=====
+I would like for you to write a C program utilizing nodes to construct a simple list, joining new values onto the end of the last node.
+The program should do the following:
+  * implement a node containing signed char's (for **value**)
+  * prompt the user to enter a value (-1 to exit)
+  * allocate a node (or the next node-- you'll have to deal with first vs. remaining case logic)
+  * obtain input from the user and assign it to the current node
+  * once a -1 has been provided, display the list from beginning to end and then exit
+Sample output would look as follows:
+<cli>
+lab46:~/src/data$ ./node
+Enter a value (-1 to quit): 12
+Enter a value (-1 to quit): 37
+Enter a value (-1 to quit): 8
+Enter a value (-1 to quit): 59
+Enter a value (-1 to quit): 86
+Enter a value (-1 to quit): 4
+Enter a value (-1 to quit): -1
+List: 12 -> 37 ->  8 -> 59 -> 86 ->  4 -> NULL
+lab46:~/src/data$
+</cli>
+NOTE: This is just example input. Not only should your program work with this, but lists of any length, containing any arrangement of valid values.
+=====Submission=====
+To successfully complete this project, the following criteria must be met:
+  * Handwritten diagram fully detailed for an 8 node list uploaded to your Opus
+    * insert the image into your journal, and have related commentary on what is going on
+    * submit the URL (to that week's journal entry) along with your program
+  * Code must compile cleanly (no warnings or errors)
+  * Executed program must display in a manner similar to provided output.
+  * Output must be correct
+  * Code must be nicely and consistently indented (you may use the **indent** tool)
+  * Code must be commented
+    * have a properly filled-out comment banner at the top
+    * have at least 20% of your program consist of **<nowiki>//</nowiki>**-style descriptive comments
+  * Track/version the source code in a repository
+  * Submit a copy of your source code to me using the **submit** tool.
+To submit this program to me using the **submit** tool, run the following command at your lab46 prompt:
+<cli>
+$ submit data nodes node.c http://lab46.corning-cc.edu/opus/SEMESTER/user/start#week_2
+Submitting data project "nodes":
+    -> node.c(OK)
+    -> http://lab46.corning-cc.edu/opus/SEMESTER/user/start#week_2(OK)
+SUCCESSFULLY SUBMITTED
+</cli>
+You should get some sort of confirmation indicating successful submission if all went according to plan. If not, check for typos and or locational mismatches.

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